Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: philipb on 12 March 2008, 20:24:04

Title: auto back axle "thump"
Post by: philipb on 12 March 2008, 20:24:04
Can anyone please advise if it normal when putting the car in drive there is a "thump" comes from the back axle area. 2.5 covered 90,000 miles, it has always done this ,since I have had the car, but it beng my first automatic assumed it was normal, now not so sure.
 Also any ideas what would cause a slight pulling to the left (not road camber) this is something that has recently started.Many thanks
Title: Re: auto back axle "thump"
Post by: achoo81 on 12 March 2008, 20:39:11
No that is not normal, check all the mounting points inc any nuts and bolt for tightness ,also check all rubber mountings for damage or excessive movement. Also check the nuts and bolts on both ends of the prop shaft are not loose.
Title: Re: auto back axle "thump"
Post by: minimeee on 12 March 2008, 20:40:12
i've got 2.2 auto and there's defo no thump goin into drive, no idea what may cause it
Title: Re: auto back axle "thump"
Post by: Ironingboard on 12 March 2008, 23:45:42
Quote
Can anyone please advise if it normal when putting the car in drive there is a "thump" comes from the back axle area. 2.5 covered 90,000 miles, it has always done this ,since I have had the car, but it beng my first automatic assumed it was normal, now not so sure.
 Also any ideas what would cause a slight pulling to the left (not road camber) this is something that has recently started.Many thanks

Hey philipb, I had a thump coming from the back of my omega at 75k miles. Couldn't find out what it was until I put my foot on the brake and tried to move the car forward and reverse while braking. You need to dip the accelerator quickly to try this out. If there's a thump then the sound might be coming from the rear differential mounts.

They are two mounting blocks which sit horizontally which the differential sits on using a bolt through each block. Difficult to describe but I hope you know what I mean.

Bit of a pain to check since the weight needs to come off the differential, only way of doing that is as described above. Get someone in budget or kwik fit to sit in the car on the ramp and get them to try out the technique. You should see the differential lift up with the rubber coming away from the metal frame of the mount. Well that’s what happened with my mounts.  :)

Around £28 each from vx  :o
Title: Re: auto back axle "thump"
Post by: Varche on 13 March 2008, 11:37:04
The other suggestions are well worth exploring.

Has the auto box had an oil change? If not when you do it you may find bits of the thrust washer in the smaller of the two sumps. I think that a failed washer causes a similar thump.

varche
Title: Re: auto back axle "thump"
Post by: Marks DTM Calib on 13 March 2008, 11:50:34
The first thing to check is the rear brake and hand brake.....
Title: Re: auto back axle "thump"
Post by: Jimbob on 13 March 2008, 12:37:49
Very occasionally, I get a thump from the back, going from reverse to drive, I've put it down to the car not being fully stationary, but maybe more to it.
Title: Re: auto back axle "thump"
Post by: Marie on 13 March 2008, 12:56:27
mine does this thumpin its not that bad but i beleive its the differental needin an oil change. the diff is weeping slightly but i am not takin the risk. so when easter comes round i will be doing this.
Title: Re: auto back axle "thump"
Post by: philipb on 14 March 2008, 17:43:25
Many thanks for your replies, will hopefully have time this weekend to check some of them out.
Philipb